I don't think he cared at that point, seeing as they would be part of it soon anyway. It probably wasn't the first time for them, hence lock and bolts (would it really stop a bandit that really wanted in?)

Lee notices a gun on Andy when they enter the dining room. Andy was just being cool to prevent a scene. I was mad that you couldn't make one then and there. It was obvious that was a human slaughterhouse from the implements to the JARS FILLED WITH HUMAN ORGANS.

Andy's explanation does make sense. Lee, Mark and Kenny were hunting not that long ago, so I don't think he is a stranger to that amount of fluids. No water to wash the blood away and all that. Who would suspect a cannibalism after 3 months at our day and age ? The bear trap was a bit suspicious though, why remove the release mechanism ...